A pad used for a display apparatus comprises a metal sublayer with a relatively weak corrosion resistance, which is revealed at an edge of the pad, and the revealed metal sublayer may be damaged and thereby the pad and the display apparatus are impaired when an electrode etching process is subjected to an electrode in a display area.
In order to prevent the occurrence of the problem described above, the edge of the pad is typically covered with a pixel defining layer material such as polyimide or poly(methyl methacrylate). However, since the pixel defining layer is typically thick, the pixel defining layer covering the pad area is required to be thinned in order not to influence the quality of welding. This thinning is required to be performed by using a half-tone mask, then depositing a conductive material layer, and etching the conductive material layer, and thus the cost increases and the process becomes complex.